Data collection was begun on the project in February 1994. By the end of July 1994, 48 subjects were studied. We have identified a foreign visiting scientist with expertise in transcranial doppler to work with us on this program. At present, that person cannot be brought on board because of the current federal hiring freeze. The hiring freeze has resulted in the limited number of studies and the delay in starting this project. With the current limitations, we project to collect data on about 200-250 BLSA participants during the coming year. The focus of the project over the past year has been to be certain of the accuracy and reliability of the measurements. The current protocol is dependent on the skills of the sonogapher. A protocol has been developed for monitoring studies and to monitor the consistency of studies over time, and the accuracy of the equipment.